Tire pressure monitoring systems having a pressure sensor and radio frequency (“RF”) transmitter in each tire to transmit pressure information are known. Other information such as the tire's identification my also be transmitted. Various arrangements have been proposed for the on-board vehicle controller to associate the tire's identification code with the tire's location on the vehicle.
It is desirable to inform the vehicle driver which tire, by position on the vehicle, has low pressure. To do so, the tire pressure monitor system must be able to identify which tire pressure monitor transmitted a signal indicating low tire pressure. Therefore, each signal must be linked to its corresponding tire location. Since the transmitted RF signal includes an identifying code which differs for each tire on the vehicle, the tire pressure monitor system must associate or learn the vehicle tire location position with each identifying code.
One way to accomplish this learning or association is to place a low frequency (“LF”) initiator in each wheel well and a corresponding LF receiver in each tire. Each LF initiator is then individually commanded to initiate an output signal that results in its associated tire receiving the LF signal and then transmitting an RF signal in response thereto including transmitting its identification (“ID”) code. The vehicle's on-board RF receiver receives the response signal and records that ID code for that tire location. Any subsequently received signals with that ID code during vehicle use will be associated with that tire location for display on the vehicle cabin display for the vehicle driver. The pressure and tire position may be correlated this way. However, it is expensive to have a LF initiator located in each wheel well.